Implementing MPLS Transport Profile

This module describes how to implement MPLS transport profile (MPLS-TP) on the router. MPLS-TPsupported by IETF enables the migration of transport networks to a packet-based network that efficientlyscale to support packet services in a simple and cost-effective way.MPLS-TP combines the necessary existingcapabilities of MPLS with additional minimal mechanisms in order that it can be used in a transport role.

MPLS transport profile enables you to create tunnels that provide the transport network service layer overwhich IP and MPLS traffic traverse.

Feature History for Implementing MPLS Transport Profile

ModificationRelease

This feature was introduced.Release 4.2.0

• Restrictions for MPLS-TP, page 1

• Information About Implementing MPLS Transport Profile, page 2

• How to Implement MPLS Transport Profile, page 6

Restrictions for MPLS-TP• Penultimate hop popping is not supported. Only ultimate hop popping is supported, because labelmappings are configured at the MPLS-TP endpoints.

• MPLS-TP links must be configured with IP addresses.

• IPv6 addressing is not supported.

L2VPN Restrictions

• Pseudowire ID Forward Equivalence Class (FEC) (type 128) is supported, but generalized ID FEC (type129) is not supported.

• BFD over pseudowire is not supported. Static pseudowire OAM protocol is used to signal fault on staticpseudowire placed over TP tunnels using pseudowire status.

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• Only Ethernet pseudowire type is supported.

Information About Implementing MPLS Transport ProfileTo implement MPLS-TP, you should understand these concepts:

MPLS Transport ProfileMPLS Transport Profile (TP) enables you to create tunnels that provide the transport network service layerover which IP and MPLS traffic traverse. MPLS-TP tunnels enable a transition from Synchronous OpticalNetworking (SONET) and Synchronous Digital Hierarchy (SDH) time-division multiplexing (TDM)technologies to packet switching, to support services with high bandwidth utilization and low cost. Transportnetworks are connection oriented, statically provisioned, and have long-lived connections. Transport networksusually avoid control protocols that change identifiers like labels. MPLS-TP tunnels provide this functionalitythrough statically provisioned bidirectional label switched paths (LSPs). This figure shows the MPLS-TPtunnel:

Figure 1: MPLS Transport Profile Tunnel

MPLS-TP combines the necessary existing capabilities of MPLS with additional minimal mechanisms inorder that it can be used in a transport role. You can set upMPLS-TP through a CLI or a network managementsystem.

MPLS-TP tunnels have these characteristics:

• An MPLS-TP tunnel can be associated with working LSP, protect LSP, or both LSP

• Statically provisioned bidirectional MPLS-TP label switched paths (LSPs)

• Symmetric or asymmetric bandwidth reservation

• 1:1 path protection with revertive mode for MPLS-TP LSP with revertive mode for MPLS-TP LSP

• Use of Generic Alert Label (GAL) and Generic Associated Channel Header (G-ACH) to transport controlpackets; for example, BFD packets and pseudowire OAM packets

• BFD is used as a continuity check (CC) mechanism over MPLS-TP LSP

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Implementing MPLS Transport ProfileInformation About Implementing MPLS Transport Profile

• Remote Defect Indication (RDI) based on BFD

• Fault OAM functions

These services are supported over MPLS-TP tunnels:

• Dynamic spoke pseudowire (for H-VPLS) over static MPLS-TP tunnels.

• Static spoke pseudowire (for H-VPLS) over static MPLS-TP tunnels.

• MS-PW services where static and dynamic pseudowire segments can be concatenated.

• MPLS ping and traceroute over MPLS TP LSP and PW.

• Static routes over MPLS-TP tunnels.

• Pseudowire redundancy for static pseudowire.

• VPWS using static or dynamic pseudowire pinned down to MPLS-TP tunnels.

• VPLS and H-VPLS using static or dynamic pseudowire pinned down to MPLS-TP tunnels.

Bidirectional LSPsMPLS transport profile (MPLS-TP) LSPs are bidirectional and congruent where LSPs traverse the same pathin both directions. AnMPLS-TP tunnel can be associatedwith either workingMPLS-TP LSP, protectMPLS-TPLSP, or both. The working LSP is the primary LSP backed up by the protect LSP. When a working LSP goesdown, protect LSP is automatically activated. In order for an MPLS-TP tunnel to be operationally up, it mustbe configured with at least one LSP.

MPLS-TP Path ProtectionPath protection provides an end-to-end failure recovery mechanism (that is, full path protection) for MPLS-TPtunnels. MPLS-TP LSPs support 1:1 path protection. You can configure the working and protect LSPs as partof configuring the MPLS-TP tunnel. The working LSP is the primary LSP used to route traffic, while theprotect LSP is a backup for a working LSP. If the working LSP fails, traffic is switched to the protect LSPuntil the working LSP is restored, at which time traffic forwarding reverts back to the working LSP (revertivemode).

Fault OAM SupportThe fault OAM protocols and messages support the provisioning and maintenance of MPLS-TP tunnels andbidirectional LSPs:

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Implementing MPLS Transport ProfileBidirectional LSPs

• Generic Associated Channel

Generic Associated Channel (G-ACh) is the control channel mechanism associated with MPLSLSPs in addition to MPLS pseudowire. The G-ACh Label (GAL) (Label 13) is a generic alertlabel to identify the presence of the G-ACh in the label packet. It is taken from the reservedMPLSlabel space.

G-ACh or GAL is used to support in-band OAMs ofMPLS-TP LSPs and pseudowires. The OAMmessages are used for fault management, connection verification, continuity check and otherfunctions.

These messages are forwarded along the specified MPLS LSP:

• OAMFault Management: Alarm Indication Signal (AIS), Link Down Indication (LDI), andLock Report (LKR) messages (GAL with fault-OAM channel)

• OAM Connection Verification: Ping and traceroute messages (GAL with IP channel)

• BFD messages (GAL with BFD channel)

These messages are forwarded along the specified pseudowire:

• Static pseudowire OAM messages (static pseudowire status)

• Pseudowire ping and traceroute messages

• Fault Management: Alarm Indication Signal (AIS), Link Down Indication (LDI), and LockReport (LKR) messages

LDI messages are generated at midpoint nodes when a failure is detected. The midpoint sendsthe LDI message to the endpoint that is reachable with the existing failure. The midpoint nodealso sends LKR messages to the reachable endpoint, when an interface is administratively down.AIS messages are not generated by Cisco platforms, but are processed if received. By default, thereception of LDI and LKR on the active LSP at an endpoint will cause a path protection switchover,while AIS will not.

• Fault Management: Emulated Protection Switching for LSP Lockout

You can implement a form of Emulated Protection Switching in support of LSP Lockout usingcustomized fault messages. When a Cisco Lockout message is sent, it does not cause the LSP tobe administratively down. The Cisco Lockout message causes a path protection switchover andprevents data traffic from using the LSP. The LSP's data path remains up so that BFD and otherOAM messages can continue to traverse it. Maintenance of the LSP can take place such asreconfiguring or replacing a midpoint LSR. BFD state over LSP must be up and MPLS ping andtraceroute can be used to verify the LSP connectivity, before the LSP is put back into service byremoving the lockout. You cannot lockout working and protect LSPs simultaneously.

• LSP ping and traceroute

For MPLS-TP connectivity verification, you can use ping mpls traffic-eng tunnel-tp andtraceroute mpls traffic-eng tunnel-tp commands. You can specify that the echo requests be sentalong the working LSP or the protect LSP. You can also specify that the echo request be sent ona locked out MPLS-TP tunnel LSP (either working or protect) if the working or protect LSP isexplicitly specified.

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Implementing MPLS Transport ProfileFault OAM Support

• Continuity Check through BFD

BFD session is automatically created onMPLS-TP LSPs with default parameters. You can overridethe default BFD parameters either through global commands or per-tunnel commands. Furthermore,you can optionally specify different BFD parameters for standby LSPs. For example, when anLSP is in standby, BFD hello messages can be sent at smaller frequency to reduce line-card CPUusage. However, when a standby LSP becomes active (for example, due to protection switching),nominal BFD parameters are used for that LSPs (for example, to run BFD hello messages at higherfrequency). For more information about BFD, see the Configuring Bidirectional ForwardingDetection on the Cisco ASR 9000 Series Router in the Cisco ASR 9000 Series AggregationServices Router Interface and Hardware Component Configuration Guide.

MPLS-TP Links and Physical InterfacesMPLS-TP link IDs may be assigned to physical interfaces only. Bundled interfaces and virtual interfaces arenot supported for MPLS-TP link IDs.

The MPLS-TP link is used to create a level of indirection between the MPLS-TP tunnel and midpoint LSPconfiguration and the physical interface. The MPLS-TP link-id command is used to associate an MPLS-TPlink ID with a physical interface and next-hop node address.

Multiple tunnels and LSPs may then refer to the MPLS-TP link to indicate they are traversing that interface.You canmove theMPLS-TP link from one interface to another without reconfiguring all theMPLS-TP tunnelsand LSPs that refer to the link.

Link IDs must be unique on the router or node. For more information, see the Configuring MPLS-TP Linksand Physical Interfaces section.

Tunnel LSPsTunnel LSPs, whether endpoint or midpoint, use the same identifying information. However, it is entereddifferently.

• A midpoint consists of a forward LSP and a reverse LSP. A MPLS-TP LSP mid point is identified byits name, and forward LSP, reverse LSP, or both are configured under a submode.

• At the midpoint, determining which end is source and which is destination is arbitrary. That is, if youare configuring a tunnel between your router and a coworker's router, then your router is the source.However, your coworker considers his or her router to be the source. At the midpoint, either router couldbe considered the source. At the midpoint, the forward direction is from source to destination, and thereverse direction is from destination to source. For more information, see the Configuring MPLS-TPLSPs at Midpoints section.

• At themidpoint, the LSP number does not assume default values, and hencemust be explicitly configured.

• At the endpoint, the local information (source) either comes from the global node ID and global ID, orfrom locally configured information using the source command after you enter the interface tunnel-tpnumber command, where number is the local or source tunnel-number.

• At the endpoint, the remote information (destination) is configured using the destination command afteryou enter the interface tunnel-tp number command. The destination command includes the destination

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node ID, optionally the global ID, and optionally the destination tunnel number. If you do not specifythe destination tunnel number, the source tunnel number is used.

MPLS-TP IP-less supportGenerally,MPLS-TP functionality can be deployedwith or without an IP address. However, themainmotivationfor the IP-less model is this: an LSR can be inserted into an MPLS-TP network without changing theconfigurations on adjacent LSRs. In the past Cisco IOS-XR MPLS-TP release, if an interface does not havea valid IP address, BFD packets cannot be transmitted over that link, and hence MPLS-TP LSP cannot bebrought up on that link. In this release, the IP-less TP link operates only in a point-to-point mode.

This feature, therefore, makes the need for an IP address on a TP link optional. You may deploy LSRs runningCisco IOS-XR inMPLS-TP networks with or without an IP address.With such extra flexibility, LSRs runningCisco IOS-XR can be easily deployed not only with LSRs running IOS, but with LSRs from other vendorstoo.

How to Implement MPLS Transport ProfileMPLS Transport Profile (MPLS-TP) supported by IETF enables the migration of transport networks to apacket-based network that efficiently scale to support packet services in a simple and cost effective way.

These procedures are used to implement MPLS-TP:

Configuring the Node ID and Global IDPerform this task to configure node ID and global ID on the router.

SUMMARY STEPS

1. configure2. mpls traffic-eng3. tp4. node-id node-id5. global-id num6. commit

DETAILED STEPS

PurposeCommand or Action

configureStep 1

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PurposeCommand or Action

Enters MPLS TE configuration mode.mpls traffic-eng

Example:

RP/0/RSP0/CPU0:router(config)# mplstraffic-eng

Step 2

Enters MPLS transport profile (TP) configuration mode. You canconfigure MPLS TP specific parameters for the router from thismode.

tp

Example:

RP/0/RSP0/CPU0:router(config-mpls-te)#mpls tp

Step 3

Specifies the defaultMPLS TP node ID, which is used as the defaultsource node ID for all MPLS TP tunnels configured on the router.

node-id node-id

Example:

RP/0/RSP0/CPU0:router(config-mpls-te-tp)#node-id 10.0.0.1

Step 4

The node ID is a 32-bit number represented in IPv4address format, and can be optionally assigned to eachnode.

Note

Specifies the default global ID used for all endpoints andmidpoints.This command makes the node ID globally unique in a

global-id num

Example:

RP/0/RSP0/CPU0:router(config-mpls-te-tp)#global-id 10

Step 5

multi-provider tunnel. Otherwise, the node ID is only locallymeaningful.

The global ID is a 32-bit number, and can be assigned toeach node.

Note

commitStep 6

Configuring Pseudowire OAM AttributesPerform this task to configure pseudowire OAM attributes.

SUMMARY STEPS

1. configure2. l2vpn3. pw-oam refresh transmit value4. commit

DETAILED STEPS

PurposeCommand or Action

configureStep 1

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Implementing MPLS Transport ProfileConfiguring Pseudowire OAM Attributes

PurposeCommand or Action

Enters L2VPN configuration mode.l2vpn

Example:

RP/0/RSP0/CPU0:router(config)# l2vpn

Step 2

Specifies the OAM timeout refresh intervals.pw-oam refresh transmit value

Example:

RP/0/RSP0/CPU0:router(config-l2vpn)# pw-oam refreshtransmit 20

Step 3

commitStep 4

Configuring the Pseudowire ClassWhen you create the pseudowire class, you specify the parameters of the pseudowire, such as the use of thecontrol word and preferred path.

SUMMARY STEPS

1. configure2. l2vpn3. pw-class name4. encapsulation mpls5. preferred-path interface tunnel-tp tunnel-number6. commit

DETAILED STEPS

PurposeCommand or Action

configureStep 1

Enters L2VPN configuration mode.l2vpn

Example:

RP/0/RSP0/CPU0:router(config)# l2vpn

Step 2

Creates a pseudowire OAM class named foo andenters pseudowireOAMclass configurationmode.

pw-class name

Example:

RP/0/RSP0/CPU0:router(config-l2vpn)# pw-class foo

Step 3

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PurposeCommand or Action

Sets pseudowire encapsulation to MPLS.encapsulation mpls

Example:

RP/0/RSP0/CPU0:router(config-l2vpn-pwc)#encapsulation mpls

Step 4

Specifies TP tunnel interface 10 for thepreferred-path.

preferred-path interface tunnel-tp tunnel-number

Example:

RP/0/RSP0/CPU0:router(config-l2vpn-pwc-mpls)#preferred-path interface tunnel-tp 10

Step 5

commitStep 6

Configuring the PseudowirePerform this task to configure the pseudowire.

SUMMARY STEPS

1. configure2. interface type interface-path-id3. pseudowire-class class-name4. encapsulation mpls5. preferred-path interface tunnel-tp tunnel-number6. commit

DETAILED STEPS

PurposeCommand or Action

configureStep 1

Enters MPLS transport protocol tunnel interfaceconfiguration mode.

interface type interface-path-id

Example:

RP/0/RSP0/CPU0:router(config)# interfacetunnel-tp 20

Step 2

Creates a pseudowire class and enters pseudowire classconfiguration mode.

pseudowire-class class-name

Example:

RP/0/RSP0/CPU0:router(config-if)#pseudowire-class foo

Step 3

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PurposeCommand or Action

Specifies the encapsulation type.encapsulation mpls

Example:

RP/0/RSP0/CPU0:router# encapsulation mpls

Step 4

Specifies TP tunnel interface 10 for the preferred-path.preferred-path interface tunnel-tp tunnel-numberStep 5

Example:

RP/0/RSP0/CPU0:router# preferred-path interfacetunnel-tp 10

When a PW class with tunnel-tp interface as apreferred path is defined, this specified classcan be associated with any PW.

Note

commitStep 6

Configuring the MPLS TP TunnelOn the endpoint routers, create an MPLS TP tunnel and configure its parameters.

SUMMARY STEPS

1. configure2. interface tunnel-tp number3. description tunnel-desc4. bandwidth num5. source source node-ID6. destination destination node-ID [global-id destination global ID] tunnel-id destination tunnel ID]7. working-lsp8. in-label num9. out-label mpls label out-link link ID10. lsp-number value11. exit12. protect-lsp13. in-label num14. out-label mpls label out-link link ID15. lsp-number value16. exit17. commit

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Implementing MPLS Transport ProfileConfiguring the MPLS TP Tunnel

DETAILED STEPS

PurposeCommand or Action

configureStep 1

Enters tunnel tp interface configuration mode. Therange is from 0 to 65535.

interface tunnel-tp number

Example:

RP/0/RSP0/CPU0:router(config)# interface tunnel-tp10

Step 2

Specifies a tunnel tp description.description tunnel-desc

Example:

RP/0/RSP0/CPU0:router(config-if)# descriptionhead-end tunnel

Step 3

Specifies the tunnel bandwidth in kbps. The rangeis from 0 to 4294967295.

bandwidth num

Example:

RP/0/RSP0/CPU0:router(config-if)# tp bandwidth 1000

Step 4

Specifies the source node of the tunnel.source source node-ID

Example:

RP/0/RSP0/CPU0:router(config-if)# source 10.0.0.1

Step 5

Specifies the destination node of the tunnel.destination destination node-ID [global-id destination globalID] tunnel-id destination tunnel ID]

Step 6

Example:

RP/0/RSP0/CPU0:router(config-if)# destination10.0.0.1 global-id 10 tunnel-id 2

Specifies a working LSP, also known as the primaryLSP. This LSP is used to route traffic.

working-lsp

Example:

RP/0/RSP0/CPU0:router(config-if)# working-lsp

Step 7

Specifies the in-label.in-label num

Example:

RP/0/RSP0/CPU0:router(config-if-work)# in-label 111

Step 8

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PurposeCommand or Action

Specifies the out-label.out-label mpls label out-link link ID

Example:

RP/0/RSP0/CPU0:router(config-if-work)# out-label111 out-link 10

Step 9

Specifies the LSP ID of the working LSP.lsp-number value

Example:

RP/0/RSP0/CPU0:router(config-if-work)# lsp-number10

Step 10

Exits from working LSP interface configurationmode.

exit

Example:

RP/0/RSP0/CPU0:router(config-if-work)# exit

Step 11

Specifies a backup for a working LSP. If theworking LSP fails, traffic is switched to the protect

protect-lsp

Example:

RP/0/RSP0/CPU0:router(config-if)# protect-lsp

Step 12

LSP until the working LSP is restored, at whichtime traffic forwarding reverts back to the workingLSP.

Specifies the in-label.in-label num

Example:

RP/0/RSP0/CPU0:router(config-if-protect)# in-label113

Step 13

Specifies the out-label and out-link.out-label mpls label out-link link ID

Example:

RP/0/RSP0/CPU0:router(config-if-protect)# out-label112 out-link 2

Step 14

Specifies the LSP ID of the protect LSP.lsp-number value

Example:

RP/0/RSP0/CPU0:router(config-if-protect)# lsp-number10

Step 15

Exits from protect LSP interface configurationmode.

exit

Example:

RP/0/RSP0/CPU0:router(config-if-protect)# exit

Step 16

commitStep 17

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Implementing MPLS Transport ProfileConfiguring the MPLS TP Tunnel

Configuring MPLS-TP LSPs at MidpointPerform this task to configure the MPLS-TP LSPs at the midpoint router.

When configuring the LSPs at the midpoint routers, make sure that the configuration does not reflecttraffic back to the originating node.

Note

SUMMARY STEPS

1. configure2. mpls traffic-eng3. tp mid name4. tunnel-name name5. lsp-number value6. source node -ID tunnel-id number7. destination node -ID tunnel-id number8. commit

DETAILED STEPS

PurposeCommand or Action

configureStep 1

Enters MPLS TE configuration mode.mpls traffic-eng

Example:

RP/0/RSP0/CPU0:router(config)# mpls traffic-eng

Step 2

Specifies the MPLS-TP tunnel mid-pointidentifier.

tp mid name

Example:

RP/0/RSP0/CPU0:router(config-mpls-te)# tp mid foo

Step 3

Specifies the name of the tunnel whose midpoint is being configured.

tunnel-name name

Example:

RP/0/RSP0/CPU0:router(config-mpls-te-tp-mid)#tunnel-name midtunnel

Step 4

Specifies the LSP ID.lsp-number value

Example:

RP/0/RSP0/CPU0:router(config-mpls-te-tp-mid)# lsp-number10

Step 5

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PurposeCommand or Action

Specifies the source node ID and tunnel ID.source node -ID tunnel-id number

Example:

RP/0/RSP0/CPU0:router(config-mpls-te-tp-mid-fwd)# source10.0.0.1 tunnel-id 12

Step 6

Specifies the destination node ID and tunnelID.

destination node -ID tunnel-id number

Example:

RP/0/RSP0/CPU0:router(config-mpls-te-tp-mid-rev)# source10.0.0.2 tunnel-id 12

Step 7

commitStep 8

Configuring MPLS-TP Links and Physical InterfacesMPLS-TP link IDs may be assigned to physical interfaces only.

Bundled interfaces and virtual interfaces are not supported for MPLS-TP link IDs.Note

SUMMARY STEPS

1. configure2. mpls traffic-eng3. interface type interface-path-id4. link-id value next-hop address5. commit

DETAILED STEPS

PurposeCommand or Action

configureStep 1

Enters MPLS TE configuration mode.mpls traffic-eng

Example:

RP/0/RSP0/CPU0:router(config-mpls-te)#mpls traffic-eng

Step 2

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PurposeCommand or Action

Configures an interface type and path ID to be associated with aMPLS TE mode.

interface type interface-path-id

Example:RP/0/RSP0/CPU0:router(config-mpls-te)#interface POS 0/6/0/0

Step 3

Configures an interface type and path ID to be associated with aMPLS TE mode.

link-id value next-hop address

Example:RP/0/RSP0/CPU0:router(config-mpls-te-if)#link-id 22 next-hop 10.1.1.2

Step 4

You must provide the next-hop IPaddress.

Note

You can define a link ID once. If you attempt to use thesame MPLS-TP link ID with different interface ornext-hop address, the configuration gets rejected. Youhave to remove the existing link ID configuration beforeusing the same link ID with a different interface ornext-hop address.

Note

commitStep 5

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